闽江口短叶茳芏湿地土壤反硝化潜力

Denitrification potential of Cyperus malaccensis marsh soil in Minjiang River estuary of East China

选择闽江河口短叶茳芏湿地为研究对象，采用淹水厌氧培养法测定闽江口短叶茳芏（Cyperusmalaccensis）湿地土壤的反硝化速率、反硝化活性和对氮损失的贡献率。结果表明，短叶茳芏湿地不同土层的反硝化速率随培养时间的变化呈一阶指数衰减模型（R2≥0．90），5～10cm土层的反硝化速率最高；各土层反硝化活性随时间的变化逐渐增大，在培养末期达到最大，其中5～10cm土层反硝化活性最高，达93．92％；对氮损失贡献率的剖面分异特征与反硝化速率和反硝化活性的剖面分异特征一致，表现为上层土壤高于下层土壤。短叶茳芏湿地各层土壤的反硝化速率和反硝化活性的差异与不同土层土壤理化性质的差异有关，与土壤的粘粒含量、有机质、pH、NO，-N含量和WHC均呈正相关，与土壤砂粒含量呈负相关。

By using submerged anaerobic incubation method, this paper studied the soil denitrifi cation rate, denitrification ratio （denitrifying activity） and its contribution to the soil nitrogen loss in Cyperus malaccensis marsh in the Minjiang River estuary of East China. The denitrification rate in different soil layers varied with incubation time in firstorder exponential decay model （R2≥ 0.90） , and was the maximum in 510 cm soil layer. The denitrifying activity in different soil layers increased gradually over time, and was the highest （93.92%） in 510 cm soil layer. The nitrogen loss rate in different soil layers was in accordance with the denitrification rate and deni trifying activity. The contribution rate of denitrification to the nitrogen loss was higher in upper soil layers than in deeper soil layers. The differences in the denitrification rate and denitrifying activity in each soil layer were related to the soil physical and chemical properties, being posi tively correlated with soil pH and the contents of soil clay, organic matter, NO3N, and WHC, but negatively correlated with soil sand content.